The Use of Biological Approaches in the Treatment of Shoulder Pathology: A Critical Analysis Review

Staying out of trouble: FDA regulation of orthobiologics and the shoulder surgeon

BACKGROUND

Food and Drug Administration (FDA) regulation of orthobiologics can be challenging to interpret for the nonregulatory scientist. However, understanding how regulations apply to clinical use of these orthobiologic products is critical, as there are both ethical and legal ramifications to using orthobiologics in conflict with regulations. Recent FDA guidances have attempted to clarify these issues, although questions still remain regarding nuances in regulatory applications.

METHODS

FDA guidances, industry blogs, and relevant publications were searched for citations regarding recent orthobiologics and regulations. These sources were compiled into a current assessment of FDA regulations regarding the use of orthobiologics in the shoulder.

RESULTS

Key to understanding these regulations is the FDA differentiation of human cellular and tissue-based products into 361 and 351 category products. Although some controversy still exists, the FDA has attempted to clarify these issues with several recent guidances. Of equal importance, the FDA has ended enforcement discretion for many biologic products in June of 2021, creating a previously tolerated class of orthobiologics that now requires an Investigational New Drug application and subsequent Biologic License Application to legally market these orthobiologics. The same surgical procedure exception was further clarified in 2017 to exempt facilities from regulatory controls when specific guidelines are met.

CONCLUSIONS

This article attempts to clarify the current thinking on FDA regulations and will allow the shoulder and elbow surgeon to stay within the current bounds of ethical and legal use of these products.

Tendon progenitor cells as biological augmentation improve functional gait and reduce scar formation after rotator cuff repair

BACKGROUND

High rates of structural failure are reported after rotator cuff repairs due to inability to recreate the native enthesis during healing. The development of biological augmentation methods that mitigate scar formation and regenerate the enthesis is still an unmet need. Since neonatal enthesis is capable of regeneration after injury, this study tested whether delivery of neonatal tendon progenitor cells (TPCs) into the adult injured environment can enhance functional and structural supraspinatus enthesis and tendon healing.

METHODS

TPCs were isolated from Ai14 Rosa26-TdTomato mouse Achilles tendons and labeled using adenovirus-Cre. Fifty-two CB57BL/6J mice underwent detachment and acute repair of the supraspinatus tendon and received either a fibrin-only or TPC-fibrin gel. Immunofluorescence analysis was carried out to determine cellularity (DAPI), fibrocartilage (SOX9), macrophages (F4/80), myofibroblasts (α-smooth muscle actin), and scar (laminin). Assays for function (gait and biomechanical testing) and structure (micro-computed tomography imaging, picrosirius red/Alcian Blue staining, type I and III collagen staining) were carried out.

RESULTS

Analysis of TdTomato cells after injury showed minimal retention of TPCs by day 7 and day 14, with detected cells localized near the bursa and deltoid rather than the enthesis/tendon. However, TPC delivery led to significantly increased %Sox9+ cells in the enthesis at day 7 after injury and decreased laminin intensity across almost all time points compared to fibrin-only treatment. Similarly, TPC-treated mice showed gait recovery by day 14 (paw area and stride length) and day 28 (stance time), while fibrin-treated mice failed to recover gait parameters. Despite improved gait, biomechanical testing showed no differences between groups. Structural analysis by micro-computed tomography suggests that TPC application improves cortical thickness after surgery compared to fibrin. Superior collagen alignment at the neo-enthesis was also observed in the TPC-augmented group at day 28, but no difference was detected in type I and III collagen intensity.

CONCLUSION

We found that neonatal TPCs improved and restored functional gait by reducing overall scar formation, improving enthesis collagen alignment, and altering bony composition response after supraspinatus tendon repair. TPCs did not appear to integrate into the healing tissue, suggesting improved healing may be due to paracrine effects at early stages. Future work will determine the factors secreted by TPCs to develop translational targets.

Comparative efficacy of 5 suture configurations for arthroscopic rotator cuff tear repair: a network meta-analysis

BACKGROUND

Rotator cuff tear is one of the most common complaint with shoulder pain, disability, or dysfunction. So far, different arthroscopic techniques including single row (SR), double row (DR), modified Mason-Allen (MMA), suture bridge (SB) and transosseous (TO) have been identified to repair rotator cuff. However, no study has reported the comparative efficacy of these 5 suture configurations. The overall aim of this network meta-analysis was to analyze the clinical outcomes and healing rate with arthroscopy among SR, DR, MMA, SB and TO.

METHODS

A systematic literature was searched from PubMed, EBSCO-MEDLINE, Web of Science, google scholar and www.dayi100.com , and checked for the inclusion and exclusion standards. The network meta-analysis was conducted using Review Manager 5.3 and SATA 15.0 software.

RESULTS

Thirty-four studies were eligible for inclusion, including 15 randomized controlled trials, 17 retrospective and 2 prospective cohort studies, with total 3250 shoulders. Two individual reviewers evaluated the quality of the 34 studies, the score form 5 and 9 of 10 were attained according to the Newcastle-Ottawa Scale for the 17 retrospective and 2 prospective studies. There was no significant distinction for the Constant score among 5 groups in the 16 studies with 1381 shoulders. The treatment strategies were ranked as MMA, DR, SB, SR and TO. In ASES score, 14 studies included 1464 shoulders showed that no significant differences was showed among all 5 groups after surgery. Whereas the efficacy probability was TO, MMA, DR, SB and SR according to the cumulative ranking curve. The healing rate in 25 studies include 2023 shoulders was significant in both SR versus DR [risk ratio 0.45 with 95% credible interval (0.31, 0.65)], and SR versus SB [risk ratio 0.45 (95% credible interval 0.29, 0.69)], and no significant in the other comparison, the ranking probability was MMA, SB, DR, TO and SR.

CONCLUSION

Based on the clinical results, this network meta-analysis revealed that these 5 suture configurations shows no significant difference. Meanwhile, suture bridge may be the optimum treatment strategy which may improve the healing rate postoperatively, whereas the DR is a suboptimal option for arthroscopic rotator cuff repairs.

Biomechanical and Histopathological Analysis of a Retrieved Dermal Allograft After Superior Capsule Reconstruction: A Case Report

The purpose of this study was to evaluate biomechanical and histopathological results of a retrieved acellular human dermal allograft (AHDA) after superior capsule reconstruction (SCR). A 67-year-old man with pseudoparalysis was treated with SCR for an irreparable posterosuperior rotator cuff tear. The patient failed clinically 4.5 months postoperatively and elected to undergo reverse total shoulder arthroplasty (RTSA). At the time of RTSA, the AHDA was harvested. Biomechanical and histopathologic analyses were performed and compared to native grafts. Failure loads for the explanted graft and native grafts 1 and 2 were 158, 790, and 749 N, respectively. The stiffness values were 20.2, 73, and 100.5 N/mm. The displacement at failure for each graft was 10.1, 27.9, and 17.0 mm. Hematoxylin and eosin and Masson's trichrome staining revealed the presence of cells in all portions of the AHDA. The medial portion presented extensive cellular infiltration, the middle portion moderate, and the lateral portion the least infiltration. Although the only identifiable cells in the lateral portions were found in pockets on the interior of the graft, cells were mainly localized on the exterior. Postoperative cell incorporation could be found in acellular dermal allograft after SCR. However, biomechanical properties in the early postoperative phase were inferior compared with unimplanted allografts.